From http://www.sadikhov.com/forum/Regasm-Vs-Regsvcs_1595.html
Let’s try again
The regsvcs.exe utility registers a .NET component for .NET Enterprise Services.
The regasm.exe utility registers a .NET component for COM interoperability.
.NET framework assemblies are designed to work without using the Windows system Registry, but because you want your component to interact with COM+, you must make a Registry entry for them (…) use gacutil to install the component in the GAC and regsvcs to register the component.
After you have completed these steps, you can use Windows Component Services management console to view information about your component.
Some organizations might wish to start taking advantage of the .NET platform by developing certain key middle-tier components in managed code. However, they might still be using Visual Basic 6 or Active Server Pages for the user-interface tier. In this situation, you would want to develop new .NET components, which are visible to both COM-based client applications and managed .NET applications.
(…) To keep a consistent interface for COM callers, you should create an explicit interface for your managed class (this can be done with the Type Library Exporter utility, tlbexp.exe)
example:
c:\path> tlbexp
.dll
Use the regasm.exe command-line utility to register the component for use by COM.
example:
c:\path> regasm
.dll